I'm about to embark on the JMT the last Friday in July. I was wondering what time I have to show to be reasonably assured of a walk up permit. I believe they now give them out at 11am and am just considering my options for when to show. My default is showing the night before at midnight or 2am and just sleeping in a chair.

Does that mean there are literally four permits available for that day for what I want to do? That seems kind of insane. Actually I'm betting that's for camping right there and I could probably have a permit to pass through elsewhere?

(1) Here's a link to the map of the Valley, with the Wilderness Center marked:

http://www.nps.gov/yose/planyourvisit/upload/yosevalley2008.pdf

On this map, the post office is to the left of the WC, and left of that is the Visitors Center.

(2) Here's a link to another transportation map:

http://www.nps.gov/yose/planyourvisit/upload/valleyshuttle.pdf

On this 2d map, the backpacker's campground is directly under the "o" in the word "North" of North Pines. You can follow the paved (red-dotted) path from the backpacker's campground to the Wilderness Center, even at night. It's about a 10-15 minute walk. The number 2 in the green circle is the grocery store. You can sit outside the wilderness center and I think you'd be fine if you got there by 4 AM. Remember that you are getting a permit to start the day AFTER you pick up the permit, not that same day. So if you are starting the JMT on Friday, you need to pick up the permit on Thursday.

Edit: the museum has a movie theater showing a history of the valley thats air-conditioned, the grocery store is air-conditioned and the Awahnee has some reading rooms in the back where you could probably hang out for a few hours.

4 means 4 people not 4 permits. so a group of 4 could get a permit and take up all 4 slots on their one permit.

Last time I did a walk up in the valley was August 2009.I got to the Wilderness office around 6am and there was already a line of several people. I lucked out and got the last Pass Thru JMT slot for the next day.

There are several permit destinations leaving from the valley, you might want to walk in to the Wilderness Office, the day before you plan to get in line, to make sure you have all your information straight.